Ticket holders at this summer's Olympic Games will have something in common with non-sporting London visitors: At some point, they will want to flee the jam-packed capital. Luckily, escaping the madding crowds is as easy as hopping on a train. As a Brit who grew up near the city, here are my recommendations for 10 gold-medal-winning day trips.

Highclere Castle

The real-life Downton Abbey is an ideal day out for fans of Violet, the dowager countess. Stroll elegant staterooms and peek into posh bedrooms before descending the handsome oak staircase to the arch-lined saloon — the dramatic heart of the house as well as the blockbuster TV series. Don't miss the Egyptian Exhibition tracing the fifth Earl of Carnarvon's 1922 discovery, along with Howard Carter, of King Tutankhamen's tomb. Save time for the expansive gardens before a swish meal at the nearby Carnarvon Arms, where Downton stars stayed during recent Season 3 filming. http://www.highclerecastle.co.uk. From Paddington station to Newbury, 50 minutes plus a 15-minute cab ride.

Cambridge

Prettier than larger rival Oxford, the cobbled center of this bike-loving university town bristles with castellated old colleges, creaky-floored Tudor pubs and tomb-quiet medieval churches. Photograph the Venetian-style Bridge of Sighs over the River Cam, then nose around the lavish Fitzwilliam Museum, which is like a mini British Museum. Highlights include filigree ceramics and Technicolor Egyptian sarcophagi. Fuel up at Fort St. George — reputedly the city's oldest pub — before dropping into King's College for a choral service at one of Britain'smost beautiful chapels. http://www.visitcambridge.org. From King's Cross station, 45 minutes.

Brighton

Luring Londoners since the playboy Prince Regent began building his onion-turreted Royal Pavilion here in 1815, Brighton is the Britain's coolest seaside city. Start at the Pavilion — now a museum of gaudy palace interiors — then get lost in the labyrinthine Lanes and North Laine areas. Lined with indie shops, galleries and restaurants, this back-street tangle warrants an hour or two of on-foot retail therapy. Then hit the wind-whipped seafront: Eschew the ankle-breaking pebbly beach for Brighton Pier's slot machines, fish and chips and neon-pink, toothache-triggering peppermint rock. http://www.visitbrighton.com. From Victoria or London Bridge stations, one hour.

Canterbury Cathedral

This soaring Gothic confection in Kent — a UNESCO World Heritage Site — is the Mother Church of the Anglican faith. Check out where Thomas Becket was martyred, duck underground to the multicolumned crypt and marvel at the breathtaking stained-glass windows, including one from 1176. Before jumping back on the London-bound train, explore the town's picture-perfect medieval center, stopping at the Roman Museum and Canterbury Heritage Museum. Great old pubs abound, including the wood-beamed Parrot where Bishops Finger ale is recommended. http://www.canterbury-cathedral.org. From St. Pancras International station to Canterbury West, one hour.

Warner Bros. Studio Tour London: The Making of Harry Potter

Britain's hottest new family attraction isn't in London but in Hertfordshire. Although you won't be hopping the Hogwarts Express to get here, you'll soon be marveling at a magical array of real sets and props used to bring J.K. Rowling's fantasy world to life on the big screen. Highlights include the Great Hall, Dumbledore's office, the triple-decker Knight Bus and some scarily live-looking monsters, including a terrifying Aragog. Calm your nerves with some Butterbeer and Bertie Botts jelly beans — earwax flavor included. http://www.wbstudiotour.co.uk. From Euston to Watford Junction, 20 minutes plus a 10-minute shuttle bus ride.

The residence ofVita Sackville-Westand Harold Nicolson is even more famous for its dreamy country garden, started in the 1930s. It's a romantic fusion of fragrant herb garden, riotously hued cottage garden and delightfully monochrome White Garden, dotted with creamy irises and dahlias. Protected by the National Trust, the highlight building is the 16th century tower where Sackville-West wrote — in a room that's preserved as if she's just stepped away. http://www.nationaltrust.org.uk/sissinghurst-castle. From Charing Cross station to Staplehurst, one hour, then bus No. 5 to Sissinghurst village.

St. Albans

Arrive Wednesday or Saturday at this historic Hertfordshire city for the bustling St. Peter's Street market, then head to the cavernous cathedral. Built from 1077, it's a spectacular fusion of architectural styles from Norman to Victorian Neo-Gothic. Spot the slender bricks in its central tower: They were swiped from the ruined Roman settlement started here around 50 A.D. Head down the adjoining grassy slope toward the fascinating, Roman-focused Verulamium Museum, stopping for lunch at the wood-beamed Ye OldeFighting Cocks, reputedly England's oldest pub. http://www.stalbans.gov.uk/tourism. From St. Pancras International station, 25 minutes.

Hatfield House

Across from Hatfield station. This stately home's sweeping driveway entrance is a fitting drumroll to Britain's grandest Jacobean pile. It's lined with portrait-dotted oak paneling and centered on a magnificent wooden staircase studded with carved figures. Must-see areas include the recently restored Victorian kitchen and the sumptuous, tapestry-lined Great Hall. Pick up an audio-tour headset to learn all about the house's top-drawer history: This is where, in 1558, a young Princess Elizabeth learned of her accession to the throne. http://www.hatfield-house.co.uk. From King's Cross station to Hatfield, 30 minutes.

Culture Line

The Overground branch line weaving from East London to West Croydon is studded with small museum gems, providing a tranquil day's escape (with a handy London Travelcard transit pass) from all that Olympic mayhem. Places not to be missed include the Geffrye Museum's home interior displays; the Horniman Museum's natural history gallery; and the tiny Brunel Museum, relating the story of the first tunnel under the River Thames. The nearby Mayflower Pub is recommended for a pint and pie pit stop. And don't miss verdant Crystal Palace Park, complete with giant Victorian models of dinosaurs peeking from between its trees. http://www.cultureline.org.uk. From Highbury & Islington station.